1. Field of the Invention
The present invention relates to mechanism for protecting a magnetic disk drive. More particularly, the present invention relates to a mechanism for protecting a magnetic disk from shocks caused by a fall.
2. Description of the Related Art
In portable computers, such as notebook computers, protection of information processors from shocks caused by an accidental fall during carriage or during operation is important due to hard disk drive vulnerability to shocks and vibrations.
A magnetic disk drive reads data by making a magnetic head seek over a rotating magnetic disk. When the magnetic head collides with the magnetic disk due to a shock or vibration, the magnetic disk may be damaged, making part or all of data irrecoverable. By retracting the magnetic head from the magnetic disk, it is possible to improve shock resistance of the magnetic disk drive when a shock or vibration occurs.
Conventional magnetic disk drives are equipped with protection mechanisms including mechanisms having self-diagnostic capabilities including self-monitoring analysis and reporting technology (S.M.A.R.T) that can acquire various information about the magnetic disk drive such as spin-up time, write error, seek speed, and temperature and predict the possibility of failure.
Protective mechanisms that protect magnetic disk drives in information processors from vibrations and shocks involve retracting a magnetic head when it is detected that a computer equipped with a magnetic disk drive is tilted greatly or that a fall has started, based on output from a pressure sensor that detects changes in the weight of the magnetic disk drive. However, conditions for retraction are abstract and not definite. Thus, when a notebook computer is used on one's lap, the possibility cannot be ruled out that the protective mechanism will detect an inclination that actually will not lead to a fall, with the result that the magnetic head will be retracted unnecessarily. In that case, each time the computer tilts, the magnetic head is retracted from the magnetic disk, impairing the usability of the computer. Such protection mechanisms do reload the magnetic head when retracted by mistake.
In order to protect the magnetic disk drive of a computer from shocks caused by a fall, while maintaining the usability of the computer, it is important to retract the magnetic head by reliably detecting signs that indicate an impending shock to the magnetic disk drive, i.e., to control the retraction of the magnetic head based on conditions for retracting magnetic head specified in detail according to situations in which the computer is used or carried.
Regarding possible postures of a user when using a computer, the user may use it on a stable position such as on the desktop or on an unstable position such as on the laptop.
When the computer is used on a stable position such as on the desktop, the computer is hardly vibrated or tilted. In such a situation, the computer could be shocked greatly by a fall if the user drops the computer on the desk. In such a case, both the fall distance and the interval between the time when a vibration or inclination occurs and the time when the computer is shocked are short.
On the other hand, when the computer is used on an unstable position such as on the laptop, the computer is lightly vibrated and tilted frequently. When the computer falls, the fall distance and the interval between the time when a vibration or inclination occurs and the time when the computer is shocked is relatively long.
It is believed that the magnetic disk drive can be protected reliably without impairing its practical usability if retraction conditions for the magnetic head such as sensitivity to a fall or its signs are switched according to the above situations. Thus, it is an object of the present invention to provide an effective and highly practical magnetic disk drive protection mechanism that can closely accommodate usage situations of the computer.